Imidafenacin is an anticholinergic drug that selectively inhibits muscarinic M1 and M3 receptors and currently widely used as a therapeutic drug for urinary urgency, pollakiuria, and urge urinary incontinence caused by the overactive bladder (OAB). It is believed that imidafenacin inhibits release of acetylcholine by antagonizing M1 and contraction of bladder smooth muscles by antagonizing M3 in the urinary bladder, thereby exhibiting pharmacological effects (Non-patent literature 1).
The overactive bladder, for which efficacy and effectiveness of imidafenacin are recognized, is a syndrome characterized by urinary urgency as an essential symptom and considered to be usually with pollakiuria and nocturia (Non-patent literature 2). Further, nocturia is defined as the complaint that the individual has to wake at night 1 or more times to void and it can be troublesome in itself (Non-patent literature 3).
It has been reported that imidafenacin reduces nocturnal urine volume partially by having an antidiuretic effect through the bladder sensory nerves. However, its action mechanism is not completely understood (Non-patent literature 4).
Vasopressin is known as a hormone that controls a urinary volume. Vasopressin is a peptide which is also called as an antidiuretic hormone. As a receptor of vasopressin, V1a, V1b, and V2 receptors are known. The V2 receptor is expressed in the renal collecting tubule, and binding of vasopressin to the V2 receptor promotes reabsorption of water and then reduces the urinary volume (the antidiuretic effect). Thus, a reduction in the vasopressin action causes polyuria, nocturnal enuresis, diabetes insipidus, and the like.
Further, desmopressin is known as a V2 receptor agonist that exhibits the vasopressin-like antidiuretic action. Desmopressin is also a peptide and exhibits the antidiuretic action by selectively binding to the V2 receptor. Thus, desmopressin is currently used as a therapeutic drug for nocturnal enuresis and central diabetes insipidus.
As such, a composition containing a compound that enhances the antidiuretic effect of vasopressin or the vasopressin V2 receptor agonist is considered to be useful as a composition for preventing or treating pollakiuria, nocturia, polyuria, nocturnal polyuria, nocturnal enuresis, diabetes insipidus, and the like.